Hi Lorean, Welcome to the Board (yup yup, with capital D)
I guess, like most people say, LimeWire is the best option for Mac.
I used it to at times, although it might look unstable, i never found anything that appeared to be better.
I don't want to sound like a grumpy person but euhm... well, i would say... try to measure the benefits to the downside when you like to download a music file.
I mean, maybe it's nicer to check family and friends first to see if they don't happen to own a cd from the bands you like, than ask the cd and import it on your mac with iTunes.
That way, you can see your friends more to... even when it's just cause they buzz the door bell to ask you the cd back, hehehe